If Hekia Parata is to remain in the education portfolio for any length of time, she needs to stop spouting meaningless blather.

Repeatedly mouthing platitudes about being "passionate about raising student achievement" or "getting five out of five kids succeeding" - her latest piece of vapidity - is just not good enough coming from a front-bench minister.

Spin is one thing. Endlessly parroting a line is something else.

Someone of her seniority needs to display flexibility, even wit, and above all, the capacity to think on her feet, especially in Parliament where reputations can be built and destroyed in a matter of seconds.

It's a question of knowing when to stonewall and when to be more forthcoming. The resort to platitudes suggests a lack of confidence when the political blow-torch is directed at her portfolio.

The truth is that the Education Minister's botched handling of the cost-cutting blunder, which initially would have seen some schools losing up to five teacher positions, has brutally exposed her political shortcomings.

The Cabinet may have signed off the policy, but the buck stops with her as the responsible minister - something which, to her credit, she acknowledged while fronting Thursday's backdown.

The previous talk of Parata being a future leader of the National Party may not be totally askew. John Key obviously rates her. Her career path, which includes time in the high-powered, intellectually challenging Prime Minister's advisory unit, is positively stellar compared to some of her colleagues.

But politics demands the skills of an all-rounder. The past fortnight has revealed starkly how far she has to travel in that regard.

It now looks like her elevation to the front bench may have come too early. She was in the Cabinet for barely a year in very junior portfolios before her promotion to this role.

Little wonder she is struggling in a portfolio which has severely tested politicians of the calibre of Nick Smith, Trevor Mallard and Phil Goff in his younger days. Her poor showing has left her a passenger in the portfolio - as was the case with her predecessor, Anne Tolley.

The puzzle is why Key did not hand the portfolio to a more experienced MP from the start.

Education has been something of a Cinderella in National. As Opposition spokesman, Bill English made a substantial difference but his successors, Katherine Rich and then Tolley, didn't have the same impact.

Unlike other leaders of his party, Key saw the potential to make education a political weapon that could work for National if it sided with consumers - parents - rather than the producers - teachers.

What National forgot in recent weeks was that the consumers had been told for years smaller classes were the end-game - not bigger ones.

The subsequent backlash has probably put paid to National's intention of making education a major plank of its 2014 election campaign. It will now be counter-productive to try to do so. Opposition parties have enough ammunition to blow National out of the water.

The kudos National won from parents through national standards, offering a more accurate and honest assessment of their child's progress at school, has been negated.

National is now very much on the defensive. It may be promising to fund the training of better teachers but parents know such a programme will not bear fruit overnight.

It will have to make much more effort selling the charter school trials for which there is little public enthusiasm.

National had played a clever game of divide-and-rule in the education sector. No longer. The latest schemozzle has had the opposite effect, uniting the lobby groups. It will now be more difficult for National to introduce performance pay for teachers.

Even worse, perhaps, for National is that this episode will inevitably resurrect voters' doubts about whether the party can really be trusted at election time.

The complaint now is that National did not say anything about increasing teacher-pupil ratios in its election manifesto. But it was not looking at that time for possible budget savings.

A bigger beef can be made over Parata's over-selling of spending initiatives in the Budget. She trumpeted an extra $511.9 million over four years.

Ministers use the four-year figure because that reflects the Treasury's spending horizon. But ministers also refer to the four-year figure because it sounds like they have extracted substantial extra cash from a tight-wad Minister of Finance.

Year-by-year figures are not so flash. Asked by the Herald to provide an annual breakdown of the spending initiatives announced before last month's Budget, Parata's office was the only one of several in the Beehive which failed to supply it.

Fortunately, the Ministry of Education was not so reticent. The year-by-year amounts show, for example, that the four-year increase of $83 million in school operating grants totals only $12 million in the coming financial year.

The gutting of the revised teacher-pupil ratios means Parata will now also have to find savings of $174 million over four years to pay for those spending initiatives.

The more immediate question for National is just how big a hit it will take in the polls from the backlash.

Last week's TVNZ poll recorded near 80 per cent opposition to bigger class sizes. But the question was too loaded to have any meaning. TV3's poll this weekend may have been conducted too soon to have picked up any positives from the minister's backdown.

It is always tempting to single out events which occurred in the polling period as responsible for shifts in party allegiance.

The reality is that simple cause-and-effect propositions do not apply unless events are truly extraordinary or are of truly cataclysmic proportions. If it were just cause and effect, party support levels would oscillate wildly like demented yo-yos.

There's only one example of a sudden turnaround in support in the last decade - Don Brash's Orewa speech on the Treaty. Its success was down to it tapping directly into a strong groundswell of anti-Treaty sentiment felt by people who were frustrated they could not voice their frustration. Brash did it for them.

In Parata's case, the furore over teacher-student ratios may be the thing that tips the balance against National following a trail of mishaps and calamities in the first half of this year. Then again it may not.

Take the TVNZ poll which, despite the education meltdown, had National retaining the 47 per cent support it recorded at last year's election. Parata will be grateful for that. She can only hope TV3's poll is similarly obliging.

Herald political correspondent John Armstrong has been covering politics at a national level for nearly 30 years.
Based in the Press Gallery at Parliament in Wellington, John has worked for the Herald since 1987.
John was named Best Columnist at the 2013 Canon Media Awards and was a previous winner of Qantas media awards as best political columnist.
Prior to joining the Herald, John worked at Parliament for the New Zealand Press Association. A graduate of Canterbury University's journalism school, John began his career in journalism in 1981 on the Christchurch Star. John has a Masters of Arts degree in political science from Canterbury.